Engine-driven, electrical generators are used in a wide variety of applications. Typically, such electrical generators utilize a single driving engine directly coupled to a generator or alternator through a common shaft. Upon actuation of the engine, the crankshaft thereof rotates the common shaft so as to drive the alternator which, in turn, generates electricity. It can be appreciated that since the engine and the alternator are housed in a single enclosure, a significant amount of heat is generated within the enclosure during operation of the electrical generator.
Typically, prior electrical generators include radiators operatively connected to corresponding engines such that the engine coolant from the engines circulates through the radiators during operation of the engines. A fan, coupled to the crankshaft of the engine, rotates during operation of the electrical generator and draws air across the plurality of radiator tubes of the radiator so as to effectuate the heat exchange between the engine coolant flowing through the plurality of radiator tubes of the radiator and the air within the enclosure. In such a manner, it is intended that the air passing over the radiator tubes of the radiator having a cooling effect thereon so as to maintain the temperature of the engine coolant, and hence the temperature of the engine, below a safe operating limit.
As is known, operation of an engine driven, electrical generator can produce unwanted noise. The noise generated by the electrical generator during operation is often a result of the rotation of the fan used to cool the engine coolant flowing through the radiator tubes of the radiator of the electrical generator. Consequently, various attempts have been made to limit the time period and the speed at which the fan rotates during operation of the electrical generator to those situations wherein the engine coolant flowing through the radiator must be cooled. By way of example, a sensor may be provided to monitor the temperature of the engine coolant. The fan is operatively connected to the crankshaft of the engine only when the temperature of the engine coolant exceeds a predetermined threshold. Alternatively, in automotive applications, the fan may be connected to the crankshaft by a thermally responsive clutch. The clutch directly connects the fan to the crankshaft of the engine when the air drawn through the radiator by the fan exceeds a predetermined temperature threshold.
While these prior methods of minimizing the time period for rotating a fan of an engine-driven, electrical generator have been somewhat successful, each of these methods has significant limitations. By way of example, the use of a sensor and the associated electronics for selectively connecting the fan to the crankshaft of the engine can be cost prohibitive. Alternatively, by drawing air inward through the radiator as provided in various automotive applications, it has been found that the thermally responsive clutch interconnects the fan to the crankshaft at the engine for a longer period of time than is necessary to cool the engine coolant flowing through the radiator to a safe operating level. Hence, it can be appreciated that these prior art fan systems will generate more noise than necessary and/or desired by an end user.
Therefore, it is a primary object and feature of the present invention to provide a method and apparatus for reducing the fan noise associated with the operation of an engine driven, electrical generator.
It is a further object and feature of the present invention to provide a method and apparatus for reducing the fan noise associated with the operation of an engine driven, electrical generator that is simple and inexpensive to implement.
It is a still further object and feature of the present invention to provide a method and apparatus for reducing the fan noise associated with the operation of an engine driven, electrical generator that sufficiently cools the engine coolant flowing through the radiator of the electrical generator with the fan.
It is a still further object and feature of the present invention to provide a method and apparatus for sufficiently cooling the engine coolant flowing through the radiator of an engine for an engine-driven, electrical generator set that is adaptable for use with engines of different sizes.
In accordance with the present invention, a fan assembly is provided. The fan assembly is connectable to the crankshaft of an engine for facilitating the cooling of engine coolant flowing through a radiator. The radiator has a first side directed toward the engine and a second side. The fan assembly includes a rotatable fan positionable on the second side of the radiator. A driven pulley is operatively connected to the fan for rotational movement therewith. The fan assembly further includes a rotatable drive pulley and a fan belt system extending about the drive pulley and the driven pulley. The fan belt system translates rotation of the drive pulley to the fan. A fan clutch is also provided. The fan clutch is movable between a first disengaged position wherein the drive pulley is isolated from the crankshaft and a second engaged position wherein the fan clutch translates rotation of the crankshaft to the drive pulley in response to a predetermined temperature. The fan belt system includes a fan belt having a tension. The fan belt extends about the drive pulley and the driven pulley. The fan belt system also includes a rotatable take-up pulley. The take-up pulley is movable in order to adjust the tension of the fan belt to a user desired level.
The fan is oriented to pull air through the radiator from the first side to the second side thereof in response to rotation of the fan in a first direction. A housing element is positioned on the second side of the radiator. The housing element directs the air pulled through the radiator by the fan towards the fan clutch. The fan clutch includes a bi-metallic element for sensing the temperature of the air directed towards the fan clutch by the housing element.
In accordance with a further aspect of the present invention, a device is provided for cooling engine coolant flowing through a radiator of an engine-driven, electrical generator set. The engine has a crankshaft rotatable about a first axis and the radiator has a first side directed towards the engine and a second side. The device includes a fan positionable on the second side of the radiator. The fan is rotatable about a second axis generally parallel to the first axis. A thermally responsive clutch having a driven portion is also provided. The clutch is movable between a first disengaged position wherein the driven portion is isolated from the crankshaft and a second engaged position wherein the driven portion rotates in unison with the crankshaft in response to a predetermined temperature. A fan drive system interconnects and translates rotation of the driven portion of the clutch to the fan.
The fan drive system includes a driven pulley operatively connected to the fan for rotational movement therewith. In addition, the fan drive system includes a rotatable drive pulley and a fan belt. The rotatable drive pulley is operatively connected to the driven portion of the clutch for rotational movement therewith. The fan belt extends about the drive pulley and the driven pulley to translate rotation of the drive pulley to the driven pulley. A rotatable take-up pulley is provided to adjust the tension of the fan belt to a user-desired level.
It is contemplated for the fan to be orientated to pull air through the radiator from the first side to the second side of the radiator in response to rotation of the fan in a first direction. A housing element is positioned on the second side of the radiator to direct the air pulled through the radiator by the fan towards the clutch. The clutch includes a temperature sensing element for sensing the temperature of the air directed towards the clutch by the housing element.
In accordance with a still further aspect of the present invention, a method is provided for cooling engine coolant flowing through a radiator of an engine-driven, electrical generator set. The engine has a crankshaft rotatable about a first axis and the radiator has a first side directed towards the engine and a second side. The method includes the steps of positioning the fan on the second side of the radiator and monitoring the temperature on the second side of the radiator. The fan is rotatable about a second axis generally parallel to the first axis for drawing air through the radiator. The fan is operatively connected to the crankshaft in response to the temperature of the air on the second side of the radiator exceeding a threshold.
The fan is supported on a rotatable shaft having a driven pulley attached thereto. The driven pulley includes a groove formed therein. A drive pulley is also provided having a groove formed therein. A fan belt is positioned about the groove in the drive pulley and the groove in the driven pulley such that rotation of the drive pulley is translated to the driven pulley by the fan belt. The drive pulley is interconnected to a thermally responsive clutch. The clutch is movable between a first disengagement position wherein the drive pulley is isolated from the crankshaft and a second engaged position wherein the clutch translates rotation of the crankshaft to the drive pulley in response to the predetermined temperature. It is contemplated to disconnect the fan from the crankshaft in response to the temperature of the air on the second side of the radiator dropping below the threshold.